"The area is vast and we have our assets there. So we are investigating whether it happened in or off our waters," Harun told Bernama.

Last week, around 10 Indonesian sailors were kidnapped in waters off the southern Philippines. Manila believes the sailors were kidnapped by an Abu Sayyaf faction and were taken to the remote southern island of Sulu.

"We do take it seriously. We want to address this and the government is taking steps to address this. We have a long coastal line, from time to time, we will see what we can do – at least for the safety of the people and tourists who come here," Malaysian Foreign Minister Anifah Aman said.